↓ Advertise on Defender2 ↓

Home > Puma (Tdci) > Front wiper issue
Post Reply  Down to end
Page 1 of 1
Print this entire topic · 
blackrock



Member Since: 01 May 2022
Location: Hampshire
Posts: 54

United Kingdom 2012 Defender 110 Puma 2.2 SW Firenze Red
Front wiper issue
I have a MY2012 110 Sw and the front wipers started to have a habit of not turning off. I immediately thought it was probably the switch on the wiper motor, but oddly they seemed to switch off reliably after squirting wiper fluid, or at least after the 5/6 wipe delay. thought it might be the relay then as I couldn't see how a dodgy motor switch would behave that way. Fitted a new relay and exactly the same behaviour except that intermittent doesn't work at all now (it is a programmable intermittent relay as I wanted that function anyway). Could the motor switch cause problems that would exhibit these symptoms? I'll probably have to swap it just to see now, but I'm wondering about the stalk switch now, is that more likely?

Andrew
Post #973287 3rd Dec 2022 5:43am
View user's profile Send private message View poster's gallery Reply with quote
LR90XS2011



Member Since: 05 Apr 2011
Location: bickenhill
Posts: 3447

United Kingdom 2011 Defender 90 Puma 2.4 XS CSW Galway Green
yes quite possibly the switch is sticking and not dropping into the park position on the cam, you may be able to get some lube into it DEFENDER 90 TDCI XS,

I hope everyone is well and your land rovers make you happy
Post #973288 3rd Dec 2022 7:15am
View user's profile Send private message View poster's gallery Reply with quote
blackrock



Member Since: 01 May 2022
Location: Hampshire
Posts: 54

United Kingdom 2012 Defender 110 Puma 2.2 SW Firenze Red
I can sort of see how it could be the switch, but why would it reliably stop after the wash wipe cycle?
that's the bit that is puzzling me.

Andrew
Post #973296 3rd Dec 2022 9:36am
View user's profile Send private message View poster's gallery Reply with quote
geobloke



Member Since: 06 Nov 2012
Location: North Wales, UK
Posts: 2948

United Kingdom 
When you say not turning off, do you mean they do not park or they keep on going after you cancel the switch?
Post #973299 3rd Dec 2022 10:25am
View user's profile Send private message View poster's gallery Reply with quote
blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 15287

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
It is possible that either the stalk switch, the park switch, or even the "relay" (which isn't really a relay in the conventional sense) could be causing this, it is hard to say which is most likely without a little more information.

The park switch is a single pole double throw switch, with the common pole connected via the timer unit (aka "relay") to the stalk switch. When the stalk switch is in the "wipers off" position the common pole is connected (via the timer unit of course) to the normal (slow) speed brush of the motor. When the stalk switch is in either of the "run" positions (i.e., "normal" or "fast" speeds) the connection between the normal speed brush and the timer unit is open circuit.

The common pole of the park switch is switched between a ground connection (when the wiper sweep in in the parked position) and live feed (when the wipers are anywhere other than in the park position).

Common problems cause by a sticking park switch are either the wipers never stop running (until the ignition is switched off) which is the result of the park switch sticking in the closed-to-live (i.e., not parked) position, or the wipers don't park correctly and simply stop wherever they are when the stalk switch is set to the off position, which is caused by the park switch failing to close the contacts into the closed-to-live position. Fortunately the only other failure mode of the switch, the stuck in the closed-to-earth mode, is virtually impossible, but if it did happen there is likely to be a leakage of smoke from somewhere until a fuse blows.

I mentioned above that the connection from the common pole of the park switch is connected to the stalk switch via the delay unit (aka "relay"), and the reason for this is to support the "wipe-on-squirt" and the "intermittent wipe" functions, which are both effected in a similar manner.

When the squirt switch is pressed, the switched live from the squirt switch to the washer motor also connects a live feed to the delay unit, and this activates a relay internal to the delay unit which disconnects the normal speed motor brush from the park switch common pole, and instead connects it (the normal speed motor brush) to a live feed within the delay unit. The relay is energised by a timer circuit implemented by means of solid-state electronics within the delay unit which maintains the relay activation for a set period after the squirt switch is released, and as a result after the set period the relay de-energises and the brush feed is one again connected to the park switch common pole in the normal manner, and the normal park function works exactly as it does when the wipers are switched off after a continuous wipe (using the stalk switch) operation.

When the stalk switch is set to "intermittent wipe", a feed from the stalk switch energises another of the input pins on the delay unit, and solid state electronics once again cause a periodic activation of the same internal relay used with the squirt function. The pulse applied to the relay is of sufficient duration to move the wipers away from the park position only, the relay then deactivates and the remainder of the wiper sweep is provided by the normal wiper park function described in the first paragraphs above. On a standard relay the frequency of the pulses is fixed (so the interval between wipes is fixed) but with a less antiquated delay unit, such as the VW "99" unit, the pulse frequency can be set by driver demand allowing the variable intermittent function.

Hopefully it is clear from the above (if you've stuck with it!) that the same mechanism is used to park the wipers under all circumstances - there is only one park mechanism - so a faulty park switch will generally be apparent for normal wipe functions, squirt functions, and intermittent functions. A "stuck-to-live" fault will cause the wipers to run continuously and is hard to miss. A "stuck open circuit" fault can be more confusing, because I have come across delay units where the relay activation just happens to be of exactly the right duration for a single sweep and will stop the wipers, coincidentally, in the park position. This can be misleading when fault finding.

The symptoms you describe are inconsistent, suggesting an intermittent fault. The most likely part of the system to cause intermittent faults is the park switch, and it is also probably the cheapest component to swap on an ad-hoc basis. Unfortunately it isn't the easiest to get to, but it would be my starting point, and I feel that it is very likely to be the problem.

You could eliminate the delay unit as the cause if you remove it and carefully connect receptacles 2 and 5 in connector C0303 (the delay unit socket). This will completely remove the wipe-on-squirt and intermittent functions, and the wipers should work as simple, old-fashioned, off/normal/fast wipers with normal parking. If they do not park properly in this mode, the fault is overwhelmingly likely to be the park switch (but could, but is highly unlikely to, be the stalk switch).
Post #973313 3rd Dec 2022 11:54am
View user's profile Send private message View poster's gallery Reply with quote
blackrock



Member Since: 01 May 2022
Location: Hampshire
Posts: 54

United Kingdom 2012 Defender 110 Puma 2.2 SW Firenze Red
geobloke wrote:
When you say not turning off, do you mean they do not park or they keep on going after you cancel the switch?


By not turning off, I mean that they continue wiping even when the stalk switch is in the off position. A the moment the only way I can get them to stop (and when they stop they park in the correct position) is to do a washer 'squirt'. About 5 wipes later they stop in the parked position.

Andrew
Post #973343 3rd Dec 2022 8:42pm
View user's profile Send private message View poster's gallery Reply with quote
blackrock



Member Since: 01 May 2022
Location: Hampshire
Posts: 54

United Kingdom 2012 Defender 110 Puma 2.2 SW Firenze Red
blackwolf wrote:
It is possible that either the stalk switch, the park switch, or even the "relay" (which isn't really a relay in the conventional sense) could be causing this, it is hard to say which is most likely without a little more information.

The park switch is a single pole double throw switch, with the common pole connected via the timer unit (aka "relay") to the stalk switch. When the stalk switch is in the "wipers off" position the common pole is connected (via the timer unit of course) to the normal (slow) speed brush of the motor. When the stalk switch is in either of the "run" positions (i.e., "normal" or "fast" speeds) the connection between the normal speed brush and the timer unit is open circuit.

The common pole of the park switch is switched between a ground connection (when the wiper sweep in in the parked position) and live feed (when the wipers are anywhere other than in the park position).

Common problems cause by a sticking park switch are either the wipers never stop running (until the ignition is switched off) which is the result of the park switch sticking in the closed-to-live (i.e., not parked) position, or the wipers don't park correctly and simply stop wherever they are when the stalk switch is set to the off position, which is caused by the park switch failing to close the contacts into the closed-to-live position. Fortunately the only other failure mode of the switch, the stuck in the closed-to-earth mode, is virtually impossible, but if it did happen there is likely to be a leakage of smoke from somewhere until a fuse blows.

I mentioned above that the connection from the common pole of the park switch is connected to the stalk switch via the delay unit (aka "relay"), and the reason for this is to support the "wipe-on-squirt" and the "intermittent wipe" functions, which are both effected in a similar manner.

When the squirt switch is pressed, the switched live from the squirt switch to the washer motor also connects a live feed to the delay unit, and this activates a relay internal to the delay unit which disconnects the normal speed motor brush from the park switch common pole, and instead connects it (the normal speed motor brush) to a live feed within the delay unit. The relay is energised by a timer circuit implemented by means of solid-state electronics within the delay unit which maintains the relay activation for a set period after the squirt switch is released, and as a result after the set period the relay de-energises and the brush feed is one again connected to the park switch common pole in the normal manner, and the normal park function works exactly as it does when the wipers are switched off after a continuous wipe (using the stalk switch) operation.

When the stalk switch is set to "intermittent wipe", a feed from the stalk switch energises another of the input pins on the delay unit, and solid state electronics once again cause a periodic activation of the same internal relay used with the squirt function. The pulse applied to the relay is of sufficient duration to move the wipers away from the park position only, the relay then deactivates and the remainder of the wiper sweep is provided by the normal wiper park function described in the first paragraphs above. On a standard relay the frequency of the pulses is fixed (so the interval between wipes is fixed) but with a less antiquated delay unit, such as the VW "99" unit, the pulse frequency can be set by driver demand allowing the variable intermittent function.

Hopefully it is clear from the above (if you've stuck with it!) that the same mechanism is used to park the wipers under all circumstances - there is only one park mechanism - so a faulty park switch will generally be apparent for normal wipe functions, squirt functions, and intermittent functions. A "stuck-to-live" fault will cause the wipers to run continuously and is hard to miss. A "stuck open circuit" fault can be more confusing, because I have come across delay units where the relay activation just happens to be of exactly the right duration for a single sweep and will stop the wipers, coincidentally, in the park position. This can be misleading when fault finding.

The symptoms you describe are inconsistent, suggesting an intermittent fault. The most likely part of the system to cause intermittent faults is the park switch, and it is also probably the cheapest component to swap on an ad-hoc basis. Unfortunately it isn't the easiest to get to, but it would be my starting point, and I feel that it is very likely to be the problem.

You could eliminate the delay unit as the cause if you remove it and carefully connect receptacles 2 and 5 in connector C0303 (the delay unit socket). This will completely remove the wipe-on-squirt and intermittent functions, and the wipers should work as simple, old-fashioned, off/normal/fast wipers with normal parking. If they do not park properly in this mode, the fault is overwhelmingly likely to be the park switch (but could, but is highly unlikely to, be the stalk switch).


Excellent description, thanks, I'll have a detailed read of that together with the wiring diagram and see how it all works. I've swapped the delay unit and nothing has changed. the wipers do still stop after a squirt, though. I have a couple of switches (I bought two to see what the different between britpart and OEM was. i could see the difference genuine LR parts made as a multiplication factor) and I will fit one as soon as I have a window of opportunity.

Andrew
Post #973344 3rd Dec 2022 8:46pm
View user's profile Send private message View poster's gallery Reply with quote
blackrock



Member Since: 01 May 2022
Location: Hampshire
Posts: 54

United Kingdom 2012 Defender 110 Puma 2.2 SW Firenze Red
I had a look at the wiring diagram in the Haynes manual as the workshop manual doesn't seem to have any (!) and it shows a switch in what i assume is the stalk switch unit going to the 'ECU'. Is that the delay relay, or does it actually go to the ECU?
Anyway, I replaced the relay (with a less antiquated one, so I will have adjustable intermittent wiping) and that didn't fix anything.
I then replaced the motor park switch and that has solved the problem. And I now have adjustable intermittent wiping.

I used the procedure detailed in the LR workshop manual where you undo a set of screws holding the dash on and then pull it away from the body on the side where the motor is located. There's then enough room to get in there and swap the switch. This procedure is actually for wiper motor replacement, and it looked like that would just about be possible too.

I bought two switches, to compare Britpart against OEM. I didn't feel like paying and extra £28 or something to compare to genuine LR. The britpart looks cheaper, but had the advantage that it came with a mounting clip which the OEM one didn't, so I used Britpart. Neither looked as well made as the one I took off, so maybe the LR part is actually worth the extra £28. The OEM part definitely wasn't the same as the part I took off. The moulding looked cheaper.

So, fixed. Park switch problem. Still don't understand why I got my symptoms, unless there was a subtle mechanical reason why it would always stop after a fluid squirt.

Andrew
Post #973779 7th Dec 2022 10:19am
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2006-2023 Futuranet Ltd & Martin Lewis
DEFENDER2.NET RSS Feed - All Forums